1. Technical Field
The present invention relates to a printing control device and a printing apparatus that control formation of a pixel pattern on a medium.
2. Related Art
As printing apparatuses, ink jet printers that form a pixel pattern on a medium by ejecting ink droplets from a print head having a plurality of nozzles have been widely known. There are individual differences among the nozzles included in the print head, and accordingly, there are mismatches in the amounts of ejection, timings, and the like among the nozzles. In addition, there is a variation in the number of transports due to slippage or the like in a paper transporting process. Therefore, there are mismatches in the landing positions of dots from the nozzles. Thus, in the ink jet printers, in order to suppress or resolve joints (banding) that are generated between print widths (bands) formed by scanning of the print head each time, technology in which a lower-end portion nozzle and an upper-end portion nozzle are used for print in an overlapping manner between the bands has been proposed (for example, JP-A-2002-11859). In this printing technology, a variation in the pixel forming positions is reduced by increasing the number of nozzles that are used for a printing process, in which the lower-end portion nozzle and the upper-end portion nozzle are used in an overlapping manner, to be larger than the number of nozzles that are used for a printing process in which the lower-end portion nozzle and the upper-end portion nozzle are not used in an overlapping manner.
However, when a part of the nozzle rows are used for printing in an overlapping manner for suppressing the banding, there is a problem in that the reproducibility of the edge included in an image is lowered. In other words, the pixel forming positions are dispersed, and accordingly, there is a problem that unsteady edges are generated.
In addition, such a problem is not limited to a printing apparatus that forms a dot pattern by moving the print head in the main scanning direction and moving the medium in the sub-scanning direction, and the problem occurs commonly in a line-head-type printing apparatus that forms a dot pattern by arranging a plurality of nozzle rows in a linear pattern in the main scanning direction and moving the medium in the sub-scanning direction.